Skip to content
TapBuff
ZIP

Emerald City Mutual Water Co

What EPA’s and California’s records show in this utility’s water: nitrate, arsenic and other regulated chemicals; lead and copper; and violations since 2016, with the certification that handles each result.

Serves
26 people
Connections
11
Water source
Groundwater
Based in
Aptos, CA
County
Santa Cruz
Owner
Private
Hardness
Moderately hard

The short answer

Nothing in EPA’s and California’s records for this utility is above a health goal. That covers nitrate, arsenic and other regulated chemicals, plus lead and copper, not everything. No health-based violations on file since 2016.

What was found

Chromium (total), nitrate, fluoride and arsenic: California’s own results, samples taken from April 20, 2023 to June 2, 2026.

Below EPA’s limits3

Chromium (total)

Comes from the source

Below EPA’s limits

33ppb

Highest yearly average, 2023 to 2026

2026: not found

Averaged by year, the highest was 33 ppb, in 2023, below EPA’s legal limit of 100 ppb. In 2026, the latest year on file, it wasn’t found in its one sample.

What handles it

Nitrate

Comes from the source

Below EPA’s limits

1.3ppm

Highest sample; found in 6 of 6

2026 average: 1.3 ppm

The highest sample, in 2026, was 1.3 ppm, below EPA’s legal limit of 10 ppm. That was also the latest year on file, and its two samples averaged 1.3 ppm.

What handles it

  • NSF/ANSI 58 look for “Nitrate/Nitrite Reduction”
  • NSF/ANSI 53 look for “Nitrate/Nitrite (30 ppm challenge)”

Fluoride

Forms or is added in treatment

Below EPA’s limits

0.12ppm

Highest yearly average, 2023 to 2026

2026, one sample: 0.1 ppm

Averaged by year, the highest was 0.12 ppm, in 2023, below EPA’s legal limit of 4.0 ppm. In 2026, the latest year on file, its one sample was 0.1 ppm.

What handles it

2 compounds tested and not foundBelow the reporting level in every sample. Not found is not the same as zero.
  • Arsenic
  • Lead

Hardness

Moderately hard, 78 mg/L (4.5 grains per gallon), at its one sampling point, 2023 to 2026.

Hardness is calcium and magnesium. EPA sets no limit for it: it shows up as scale on fixtures and in water heaters, and as soap that won’t lather. USGS calls water above 60 mg/L moderately hard, above 120 hard and above 180 very hard.

Softeners compared at 4.5 grains per gallon, salt includedSoftener or salt-free conditioner?California water hardness, utility by utility

Violations since 2016

No health-based violations on file with EPA since 2016.

What this report can’t tell you

  • Everything else. Chromium (total), nitrate, fluoride and arsenic results here are California’s own from 2023 on, with EPA’s national file for 2012 to 2019. Emerald City Mutual Water Co’s own annual report, which it must send you every year, has the contaminants this page does not show.

  • Your own plumbing. Lead results are the 90th percentile across homes the utility samples. Your home’s service line, solder and fixtures decide yours. A certified lab test is the only way to know.

  • What it means for your health. This page reports what the records show and EPA’s limits and goals; it is not medical advice. If you are worried about a health effect, talk to a doctor or your local health department.

  • Anything after the latest data. SDWIS data is from 2026 Q3; UCMR 5 didn’t sample this utility; California’s results run from April 20, 2023 to June 2, 2026.

Testing your own tap

Emerald City Mutual Water Co’s results are for the water it sends out. What your own service line, solder and fixtures add shows up only in a test of your tap, by a lab California certifies.

No lab California certifies is within 75 miles of the area Emerald City Mutual Water Co serves on the state’s list. Some take samples by mail; the state’s page lists them all.

All 145 certified labs for California

Sources

PWSID CA4400667. Rebuilt from EPA data on Oct. 18, 2026.

Also in Santa Cruz County

All California utilities

What to do next